Custom Flat Fiberglass Tops for Packaged Metering Manholes

Parshall flume packaged metering manhole with flat fiberglass top Flat fiberglass tops on Packaged Metering Manholes provide a low visual profile without the need for a grade ring / frame / cover system. All fiberglass construction means the tops are corrosion-resistant and extremely strong – capable of withstanding pedestrian foot traffic and the occasional riding mower.

While strong, these fiberglass tops are lightweight, making it easy on operators:

~22 lbs. for a 48-inch diameter manhole
~35 lbs. for a 60-inch diameter manhole
~50 lbs. for a 72-inch diameter manhole

For secure areas, the flat tops can be provided with lift handles – but no locks. For areas where the manhole might be accessible to the public, an optional stainless steel padlockable hasp can be provided.

flat fiberglass manhole top mounted on a 48-inch diameter packaged metering manhole integrating a Parshall flume

While not intended to be gas-tight, the flat fiberglass top sits on / is mounted to a supporting fiberglass flange that is gasketed.

On the surface, the tops have a molded-in diamond plate surface. Unlike post-lamination finishes (i.e., sanded gel coat), the diamond plate pattern is solid and molded into the top. Even heavy foot traffic won’t wear off the slip-resistant surface.

Flat fiberglass tops are available for flow monitoring, conditioning, and control manholes with manhole diameters from 48 to 72-inches. For larger diameter manholes, an access hatch can be molded to allow access to the manhole ladder without the need to lift the entire hinged section of the top.